CN115324960A - Oil cylinder hydraulic system and overhead working machine - Google Patents
Oil cylinder hydraulic system and overhead working machine Download PDFInfo
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- CN115324960A CN115324960A CN202210876410.7A CN202210876410A CN115324960A CN 115324960 A CN115324960 A CN 115324960A CN 202210876410 A CN202210876410 A CN 202210876410A CN 115324960 A CN115324960 A CN 115324960A
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- 238000005086 pumping Methods 0.000 claims abstract description 38
- 230000008859 change Effects 0.000 claims abstract description 34
- 230000007246 mechanism Effects 0.000 claims abstract description 31
- 239000007788 liquid Substances 0.000 claims abstract description 9
- 238000006073 displacement reaction Methods 0.000 claims description 12
- 238000001514 detection method Methods 0.000 claims description 6
- 230000002441 reversible effect Effects 0.000 claims description 6
- 230000001502 supplementing effect Effects 0.000 claims description 6
- 230000002457 bidirectional effect Effects 0.000 claims description 5
- 239000003921 oil Substances 0.000 description 357
- 230000008602 contraction Effects 0.000 description 7
- 230000003068 static effect Effects 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 239000013589 supplement Substances 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000010720 hydraulic oil Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
- F15B11/17—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors using two or more pumps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
- F15B1/02—Installations or systems with accumulators
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
- F15B13/06—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with two or more servomotors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/20—Other details, e.g. assembly with regulating devices
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B19/00—Testing; Calibrating; Fault detection or monitoring; Simulation or modelling of fluid-pressure systems or apparatus not otherwise provided for
- F15B19/005—Fault detection or monitoring
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
- F15B21/04—Special measures taken in connection with the properties of the fluid
- F15B21/041—Removal or measurement of solid or liquid contamination, e.g. filtering
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fluid-Pressure Circuits (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
Abstract
The invention belongs to the field of engineering machinery, and discloses an oil cylinder hydraulic system and high-altitude operation machinery, which comprise an oil cylinder, an oil cylinder retaining valve and a leakage and temperature difference compensation oil way, wherein the oil cylinder retaining valve is arranged in an oil cylinder working oil way and is used for keeping the oil cylinder in an extending state; the leakage and temperature difference compensation oil way is provided with an oil liquid pumping mechanism and is connected with a third oil inlet and outlet of the first shuttle valve. The invention realizes the compensation of the volume change of the oil cavity of the oil cylinder caused by internal leakage and temperature difference, can ensure the stability of the extension length of the oil cylinder, and finally achieves the purposes of safety and stability of the aerial work platform.
Description
Technical Field
The invention belongs to the technical field of engineering machinery hydraulic pressure, and particularly relates to an oil cylinder hydraulic system and an aerial working machine.
Background
The hydraulic cylinder is widely used as an actuating mechanism of the high-altitude operation machine and is applied to lifting, steering and supporting functions, the hydraulic cylinder is generally provided with a balance valve, a hydraulic lock and the like and used for maintaining the pressure and the position of the hydraulic cylinder, but hydraulic valves such as the common balance valve, the hydraulic lock and the like can not avoid the existence of trace internal leakage, and hydraulic oil for supporting a piston of the hydraulic cylinder, which is sealed in the hydraulic cylinder, has the inherent characteristics of expansion with heat and contraction with cold as other substances, so that when the hydraulic cylinder extends out for a certain length and is static for a period of time in operation, the hydraulic cylinder can be observed to have certain retraction displacement.
The condition of telescopic change of the oil cylinder is ubiquitous, but unexpected displacement caused by telescopic change of the oil cylinder often causes risks to high-altitude operation, for example, the arm support moves downwards to crush a glass wall surface, a platform inclines to cause materials to fall, and the like.
Disclosure of Invention
Aiming at the defects or shortcomings, the invention discloses an oil cylinder hydraulic system and an aerial work machine, which can effectively solve the problem of expansion change of an oil cylinder caused by standing of the oil cylinder or temperature difference change.
In order to achieve the above object, the present invention discloses a cylinder hydraulic system, comprising:
the oil cylinder working oil path of the oil cylinder comprises a rodless cavity connecting oil path and a rod cavity connecting oil path;
the oil cylinder holding valve is arranged in the oil cylinder working oil way and used for keeping the oil cylinder in an extending state, the oil cylinder holding valve comprises a first shuttle valve, a first comparison oil port of the first shuttle valve is connected with the rodless cavity connecting oil way, and a second comparison oil port of the first shuttle valve is connected with the rod cavity connecting oil way;
and the leakage and temperature difference compensation oil way is provided with an oil liquid pump suction mechanism and is connected with a third oil inlet and outlet of the first shuttle valve.
In some embodiments, the oil pumping mechanism comprises an auxiliary pump capable of rotating forward and backward and an auxiliary pump driving mechanism for driving the auxiliary pump, and a first pumping oil port of the auxiliary pump is connected with a third oil inlet and outlet of the first shuttle valve; the oil cylinder hydraulic system comprises an energy accumulator, and the energy accumulator is connected with a second pumping oil port of the auxiliary pump through an energy accumulator connecting oil way.
In some embodiments, a cylinder hydraulic system comprises:
and the auxiliary oil suction oil way is connected between the second pumping oil port of the auxiliary pump and the oil tank in parallel with the energy accumulator connecting oil way, and an oil suction one-way valve which enables oil to flow to the auxiliary pump from the oil tank and is reversely cut off is arranged in the auxiliary oil suction oil way.
In some embodiments, the cylinder holding valve comprises a second shuttle valve disposed in parallel with the first shuttle valve, a first comparison port of the second shuttle valve being connected to the rodless cavity connection oil path and a second comparison port being connected to the rod cavity connection oil path;
and, the cylinder hydraulic system includes:
and the energy accumulator oil supplementing and pressure releasing oil way is connected with a third oil inlet and outlet of the second shuttle valve.
In some embodiments, an energy release valve for controlling energy release of the oil of the accumulator towards the outlet of the second shuttle valve is arranged in the oil supplementing and pressure releasing oil circuit of the accumulator, and the energy release valve comprises an energy release switch valve and a one-way throttle valve which are arranged in series.
In some embodiments, a cylinder hydraulic system comprises:
the main reversing valve comprises a main valve oil inlet, a main valve oil return port, a first working oil port connected with the rodless cavity connecting oil way and a second working oil port connected with the rod cavity connecting oil way;
the main reversing valve comprises a middle stopping position, and the first working oil port and the second working oil port are communicated with a main valve oil return port at the middle stopping position.
In some embodiments, a cylinder hydraulic system comprises:
the main pump is connected with a main valve oil inlet of the main reversing valve through a main pump oil feeding way;
and the unloading electromagnetic valve is connected between the main pump oil supply channel and the oil tank.
In some embodiments, the auxiliary pump is a bidirectional gear pump; and/or
The cylinder holding valve includes a balance valve group provided in a cylinder working oil path.
In some embodiments, a cylinder hydraulic system comprises:
the displacement sensor is used for detecting the oil cylinder elongation of the oil cylinder; and
a controller configured to:
acquiring an oil cylinder elongation signal of a displacement sensor and determining the change direction and the change value of the oil cylinder elongation of the oil cylinder;
determining that the change value is greater than a set value;
and correspondingly controlling the forward rotation starting or the reverse rotation starting of the oil liquid pumping mechanism according to the change direction until the change value is zero.
In some embodiments, a cylinder hydraulic system comprises:
the first pressure sensor is used for detecting the oil pressure of a rod cavity of the oil cylinder or a rod cavity connecting oil way;
the second pressure sensor is used for detecting the oil pressure of a rodless cavity of the oil cylinder or a rodless cavity connecting oil way; and
a controller configured to:
acquiring oil pressure detection values of a first pressure sensor and a second pressure sensor in real time, and determining a high-pressure cavity of an oil cylinder;
determining that the oil pressure detection value of a high-pressure cavity of the oil cylinder is lower than a set pressure maintaining value;
and controlling to start an oil pumping mechanism and pumping oil to a high-pressure cavity of the oil cylinder for pressure maintaining.
In some embodiments, a dwell check valve is disposed in the leak-and-temperature-difference compensation oil path, the dwell check valve being configured to enable oil to be pumped from the oil pumping mechanism to the first shuttle valve and to block in reverse.
In addition, the invention also discloses an aerial work machine which comprises the oil cylinder hydraulic system.
According to the invention, the first shuttle valve and the leakage and temperature difference compensation oil way are additionally arranged, the third oil inlet and outlet of the first shuttle valve are connected with the oil pumping mechanism through the leakage and temperature difference compensation oil way, the first comparison oil port of the first shuttle valve is connected with the rodless cavity connection oil way, and the second comparison oil port is connected with the rod cavity connection oil way, so that the high-pressure cavity of the oil cylinder is always connected with the leakage and temperature difference compensation oil way, once the elongation of the oil cylinder is greatly changed, the oil pumping mechanism can be started to pump the supplementary pressure oil to the high-pressure cavity of the oil cylinder to enable the elongation of the oil cylinder to be larger, or the oil in the high-pressure cavity is pumped by the oil pumping mechanism to enable the elongation of the oil cylinder to be smaller, and finally the oil is kept at a set position of the elongation of the oil cylinder, so that the problem of the expansion and contraction of the oil cylinder caused by the standing of the oil cylinder or the temperature difference change is effectively solved.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The accompanying drawings, which are included to provide an understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:
FIG. 1 is a hydraulic schematic of a cylinder hydraulic system according to an embodiment of the present invention;
fig. 2 is a hydraulic schematic diagram of a cylinder hydraulic system according to another embodiment of the present invention.
Description of the reference numerals
1. Main overflow valve of main pump 2
3. Unloading electromagnetic valve 4 oil filter
5. Energy release valve of main reversing valve 6
7. Oil-suction one-way valve 8 energy accumulator
9. Auxiliary pump 10 auxiliary pump driving mechanism
11. Displacement sensor for oil cylinder 12
13. Oil cylinder holding valve 14 main pump motor
15. First pressure sensor of pressure maintaining one-way valve 16
17. Second pressure sensor 18 oil tank
61. Energy release switch valve 62 one-way throttle valve
1311. First shuttle valve 1312 second shuttle valve
1321. First balance valve 1322 second balance valve
L1 leakage and temperature difference L2 energy accumulator oil supplement
Pressure relief oil way of compensation oil way
P main valve oil inlet T main valve oil return port
A1 First working oil port A2 and second working oil port
Detailed Description
The following detailed description of specific embodiments of the invention refers to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and explanatory of the invention and are not restrictive thereof.
The cylinder hydraulic system and the aerial work machine according to the present invention will be described below with reference to the accompanying drawings.
In order to compensate for a slight change in the extension length of the cylinder due to internal leakage or cold contraction, as shown in fig. 1, in an embodiment of the present invention, there is provided a novel cylinder hydraulic system, including:
the oil cylinder 11, the oil cylinder working oil circuit of the oil cylinder 11 includes the rodless cavity connecting oil circuit and the rod cavity connecting oil circuit;
the oil cylinder retaining valve 13 is arranged in the oil cylinder working oil path and used for keeping the oil cylinder 11 in an extending state, the oil cylinder retaining valve 13 comprises a first shuttle valve 1311, a first comparison oil port of the first shuttle valve 1311 is connected with a rodless cavity connecting oil path, and a second comparison oil port is connected with a rod cavity connecting oil path;
and a leakage and temperature difference compensation oil path L1 which is provided with an oil pumping mechanism and is connected with the third oil inlet and outlet of the first shuttle valve 1311.
The invention aims to design an oil cylinder hydraulic system for compensating the slight change of the extension length of an oil cylinder due to internal leakage or cold contraction. The cylinder 11 is a boom cylinder of an aerial work platform, but the cylinder of the present invention is not limited to this boom cylinder, and the present invention aims to keep the extension length of the boom cylinder at a set position relatively accurately.
Therefore, the hydraulic system is additionally provided with a first shuttle valve 1311, wherein a first comparison oil port of the first shuttle valve 1311 is connected with a rodless cavity connection oil path, and a second comparison oil port is connected with a rod cavity connection oil path; and secondly, a leakage and temperature difference compensation oil path L1 is additionally arranged, and an oil pumping mechanism is arranged in the leakage and temperature difference compensation oil path L1 and is connected with a third oil inlet and outlet of the first shuttle valve 1311. Wherein, the arrangement of the first shuttle valve 1311 ensures that the relative high-pressure chamber in the rod chamber and the rodless chamber of the oil cylinder 11 is always connected with the oil pumping mechanism; thus, when the cylinder extension of the cylinder 11 is greatly changed, the oil pumping mechanism can be started to pump additional pressure oil to the high-pressure chamber of the cylinder 11 to promote the cylinder extension to be larger, or the oil in the high-pressure chamber is pumped by the oil pumping mechanism to promote the cylinder extension to be smaller, and finally the oil is kept at a set cylinder extension position.
Compared with the prior art, the problem that the telescopic length is changed due to the leakage of the standing oil cylinder and the change of the oil temperature is not considered at all, and a corresponding telescopic length compensation scheme is not provided. Most researches are focused on the accurate control of the stretching speed and the stretching length of the oil cylinder, or the integration of a stretching displacement sensor of the oil cylinder, and the like.
Specifically, as an example, the oil pumping mechanism may include an auxiliary pump 9 capable of rotating in the forward and reverse directions and an auxiliary pump driving mechanism 10 for driving the auxiliary pump 9, such as a rotary motor or the like. In the present embodiment, the auxiliary pump 9 may be a double gear pump, and may be configured to rotate in the forward direction or the reverse direction to switch between pumping and pumping of oil. Referring to fig. 1, a first pumping port of the auxiliary pump 9 (i.e., a right end port of the auxiliary pump 9 in fig. 1) is connected to a third oil inlet and outlet of the first shuttle valve 1311, where the third oil inlet and outlet of the first shuttle valve 1311 is an oil inlet when the auxiliary pump 9 pumps oil to the high pressure chamber of the cylinder, and is an oil outlet when the auxiliary pump 9 pumps oil.
As an oil source of the make-up oil, the cylinder hydraulic system of fig. 1 may include an accumulator 8, and the accumulator 8 is connected to the second pumping port of the auxiliary pump 9 (i.e., the left port of the auxiliary pump 9 of fig. 1) through an accumulator connection oil path. Thus, when the auxiliary pump 9 pumps make-up oil to the high pressure chamber of the cylinder, the make-up oil may originate from the accumulator 8. Further, in special situations, such as when the accumulator 8 is low, the make-up fluid may also be sourced from the tank 18 or other hydraulic lines. Referring to fig. 1, an auxiliary oil suction line is further connected between the second pump oil port of the auxiliary pump 9 and the oil tank 18, and the auxiliary oil suction line is connected in parallel with the accumulator connecting oil line, so that when the auxiliary pump 9 pumps the supplementary oil to the high pressure chamber of the oil cylinder, the supplementary oil can be sourced from the oil tank 18 and pumped to the second pump oil port of the auxiliary pump 9 through the auxiliary oil suction line. In particular, the auxiliary oil suction line is also provided with an oil suction one-way valve 7 which enables oil to flow from the oil tank 18 to the auxiliary pump 9 and is cut off reversely, so that the auxiliary pump 9 can suck oil from the oil tank 18, but the oil in the high-pressure cavity of the oil cylinder can not flow back to the oil tank 18 through the auxiliary oil suction line.
Further, the cylinder holding valve 13 may further include a second shuttle valve 1312 disposed in parallel with the first shuttle valve 1311, a first comparison port of the second shuttle valve 1312 being connected to the rodless chamber connection oil path and a second comparison port being connected to the rod chamber connection oil path; and the oil cylinder hydraulic system comprises an energy accumulator oil supplementing and pressure relieving oil path L2, and the energy accumulator oil supplementing and pressure relieving oil path L2 is connected with the third oil inlet and outlet of the second shuttle valve 1312 and the energy accumulator 8. When the working circuit of the oil cylinder normally runs, high-pressure oil of the rodless cavity connecting oil way or the rod cavity connecting oil way flows to the energy accumulator 8 through the second shuttle valve 1312 and the one-way valve in the energy release valve 6 to store energy and supplement oil for the energy accumulator 8.
The accumulator oil replenishing and releasing oil passage L2 is provided with an energy releasing valve 6 for controlling the oil of the accumulator 8 to flow out toward the second shuttle valve 1312 to release energy, and the energy releasing valve 6 may include an energy releasing on-off valve 61 and a one-way throttle valve 62 arranged in series. The energy release valve 6 is used for releasing oil of the energy accumulator 8 to the oil tank 18, pressure maintaining and pressure releasing control of the energy accumulator 8 is achieved, and safety of equipment and personnel during shutdown and maintenance is guaranteed. Referring to fig. 1, neither the upper position of the energy release switch valve 61 nor the check valve of the check throttle 62 affects the oil supply of the second shuttle valve 1312 to the accumulator 8; when the energy release switch valve 61 is switched to the lower position, the oil in the accumulator 8 passes through the energy release switch valve 61 and the throttle valve in the one-way throttle valve 62 and flows to the third oil inlet and outlet of the second shuttle valve 1312.
Further, the cylinder hydraulic system includes:
the main reversing valve 5 comprises a main valve oil inlet P, a main valve oil return port T, a first working oil port A1 connected with a rodless cavity connecting oil way and a second working oil port A2 connected with a rod cavity connecting oil way;
the main directional control valve 5 includes a middle stop position, and the first working oil port A1 and the second working oil port A2 are both communicated with the main valve oil return port T at the middle stop position.
Thus, when the electromagnetic valves a and b at both ends of the main directional control valve 5 are all de-energized, the main directional control valve 5 is switched to its middle stop position, the first working oil port A1 and the second working oil port A2 of the main directional control valve 5 are both communicated with the main valve oil return port, and at this time, the energy releasing oil of the energy accumulator 8 passes through the second shuttle valve 1312, the first working oil port A1 or the second working oil port A2, and the main valve oil return port T and the oil return tank 18.
In addition, the cylinder hydraulic system further includes:
the main pump 1 is connected with a main valve oil inlet of the main reversing valve 5 through a main pump oil feeding path;
and the unloading electromagnetic valve 3 is connected between the main pumping oil path and the oil tank 18.
When the main pump 1 is started, oil can be pumped to a main valve oil inlet P of the main reversing valve 5 through a main pump oil feeding path, the oil cylinder is driven to stretch and retract through an oil cylinder working oil path, and at the moment, the unloading electromagnetic valve 3 is in a cut-off state, namely, the unloading electromagnetic valve 3 in fig. 1 is in an electrified right position. When the oil cylinder 11 is not required to be driven, the unloading electromagnetic valve 3 can be controlled to lose power and switched to the left position, and pressure oil pumped by the main pump 1 through the main pumping oil way can return to the oil tank 18 through the unloading electromagnetic valve 3.
More specifically, the main pump 1 may be a conventional unidirectional pump, and the auxiliary pump 9 may be a bidirectional gear pump. Leakage and difference in temperature compensation oil circuit L1 adopts two-way gear pump, and energy storage ware 8 is connected to its oil inlet, and the high pressure chamber of hydro-cylinder is connected to the oil-out, makes the gear pump both ends pressure differential less, selects under the circumstances of little discharge capacity gear pump, and the power of auxiliary power can accomplish very little, is favorable to the control of energy consumption. The cylinder holding valve 13 provided in the cylinder operation oil path may include a balance valve group, such as a first balance valve 1321 and a second balance valve 1322 shown in fig. 1, provided in the cylinder operation oil path in addition to the first and second shuttle valves 1311 and 1312. The conventional hydraulic valves such as a balance valve cannot avoid the problems of micro internal leakage and the like, and can cause the telescopic quantity of the oil cylinder to change.
On the basis of the oil cylinder hydraulic system, in order to realize more accurate control, the invention can further comprise:
a displacement sensor 12 for detecting the cylinder extension amount of the cylinder 11; and
a controller configured to:
acquiring an oil cylinder elongation signal of the displacement sensor 12 and determining the change direction and the change value of the oil cylinder elongation of the oil cylinder 11;
determining that the change value is greater than a set value;
and correspondingly controlling the forward rotation starting or the reverse rotation starting of the oil liquid pumping mechanism according to the change direction until the change value is zero.
The controller is used for correspondingly controlling the oil pumping mechanism to pump oil to the high-pressure cavity of the oil cylinder or pump oil from the high-pressure cavity according to the change direction and the change value of the elongation of the oil cylinder, so that the oil cylinder is enabled to stretch and retract, the elongation of the oil cylinder returns to a set value, and the oil cylinder is stably kept in the original stretching stable state. The set value may be a single value or a threshold range, and the specific value may be specifically set according to a specific working condition.
In another embodiment, as shown in fig. 2, the cylinder hydraulic system may include:
the first pressure sensor 16 is used for detecting the oil pressure of a rod cavity of the oil cylinder 11 or an oil path connected with the rod cavity;
the second pressure sensor 17 is used for detecting the oil pressure of a rodless cavity of the oil cylinder 11 or an oil path connected with the rodless cavity; and
a controller configured to:
acquiring oil pressure detection values of a first pressure sensor 16 and a second pressure sensor 17 in real time, and determining a high-pressure cavity of the oil cylinder 11;
determining that the oil pressure detection value of the high-pressure cavity of the oil cylinder 11 is lower than a set pressure maintaining value;
and controlling to start an oil pumping mechanism and pumping oil to a high-pressure cavity of the oil cylinder 11 for pressure maintaining.
Therefore, the pressure values of the two oil cavities of the oil cylinder 11 can be monitored in real time, and the pressure of the high-pressure cavity (support cavity) of the oil cylinder 11 can be maintained through the leakage and temperature difference compensation oil way L1 according to application requirements when necessary.
In particular, in this embodiment, a pressure maintaining check valve 15 is further disposed in the leakage and temperature difference compensating oil path L1, and the pressure maintaining check valve 15 is configured to enable oil to be pumped from the oil pumping mechanism to the first shuttle valve 1311 and to be cut off in the opposite direction, so as to achieve the purpose of maintaining pressure in the high pressure chamber of the oil cylinder.
The oil cylinder hydraulic system is particularly suitable for high-altitude operation machinery with an arm support oil cylinder, and the change of the oil cylinder extension of the arm support oil cylinder can bring more serious results by amplifying the change stroke of the arm support, so that the oil cylinder extension is more necessary to be accurately controlled. The oil cylinder hydraulic system designed by the invention can be used for keeping the extension length of the arm support oil cylinder of the aerial work platform in operation at a set position relatively accurately, wherein the extension length of the oil cylinder is slightly changed due to internal leakage or cold contraction.
The detailed operation of the hydraulic system of the cylinder according to the present invention under various operating conditions is described in detail with reference to fig. 1.
When the system works normally, the oil cylinder; 11 require a reversing, variable speed movement in response to a control signal. At the moment, the unloading electromagnetic valve 3 is electrified, the main pump 1 provides pressure oil, the oil flows into the oil cylinder 11 through the main reversing valve 5 with the proportion electromagnet at two ends and the oil cylinder retaining valve 13, meanwhile, the oil flows into the energy accumulator 8 through the second shuttle valve 1312 and the energy release valve 6, the energy accumulator 8 is generally used for volume compensation, the internal volume of the energy accumulator 8 is small compared with that of the oil cylinder 11, the oil charging time is extremely short, and the action of the oil cylinder 11 cannot be obviously influenced.
The size and the direction of oil flowing into the oil cylinder 11 can be controlled by controlling the coil current of the proportional electromagnets a and b at the two ends of the main reversing valve 5, so that the speed and the direction of the oil cylinder during normal operation are controlled. The pressure in the accumulator 8 is the same as the high side of the second shuttle valve 1312 and the accumulator 8 can be charged no matter which direction the cylinder 11 is charged.
When the system is in standby, the unloading electromagnetic valve 3 is de-energized, oil liquid of the main pump 1 flows back to the oil tank 18 through the unloading electromagnetic valve 3, the system is unloaded, and the oil cylinder 11 stops moving. Or when the system is stopped, the main pump 1 does not output oil outwards, and the oil cylinder is static. The cylinder 11 is kept in a stationary state by the cylinder holding valve 13 regardless of the system standby or stop.
The following explains the situation when the oil cylinder is static and needs to be compensated for internal leakage and temperature difference. The oil cylinder 11 is kept in a static state under the action of the oil cylinder holding valve 13, but hydraulic elements are not absolutely sealed in practical application, so that a trace amount of internal leakage exists in the first balance valve 1321 and the second balance valve 1322, and meanwhile, if the temperature of oil entering the oil cylinder 11 is different from the environment, when the standing time of the oil cylinder 11 is long enough and the oil temperature is reduced to the environment temperature (most of the oil temperature in practical application is higher than the environment temperature), the expansion and contraction characteristics of the oil cause the elongation change of the oil cylinder, and in practical application, the larger the temperature difference between the oil temperature and the environment is, the longer the standing time of the oil cylinder is found, the more obvious the elongation change of the oil cylinder is, and the internal leakage exists, so that the elongation of the oil cylinder in the standing state is influenced by the two components together.
At this time, the controller detects the change and direction of the cylinder extension amount of the cylinder 11 through the displacement sensor 12, the oil in the cylinder leaks outwards from the high pressure chamber (i.e. the support chamber), and when the internal leakage occurs, the pressure of the other chamber opposite to the high pressure chamber is reduced until the pressure is zero. Whether the high pressure chamber is a rod chamber or a rodless chamber, the high pressure chamber of the cylinder 11 is automatically selected by the first shuttle valve 1311.
When the volume of the high-pressure cavity of the oil cylinder 11 changes and exceeds the set deviation value of the control system, the auxiliary pump driving mechanism 10 is started and drives the auxiliary pump 9 to rotate, the auxiliary pump 9 pumps the oil in the energy accumulator 8, and the oil is supplemented to the cavity with the reduced volume through the first shuttle valve 1311 until the oil cylinder elongation of the oil cylinder 11 is recovered to the initial set value, so that the volume of the high-pressure cavity (namely, the support cavity) of the oil cylinder 11 is kept constant. The extending length of the oil cylinder 11 can be stable and unchanged by repeating the steps.
If the oil temperature is lower than the ambient temperature, namely the oil cylinder 11 stands for a long time, when the oil temperature in the cylinder body rises to the ambient temperature, due to the characteristic of expansion with heat and contraction with cold of the oil, the high-pressure cavity of the oil cylinder 11 changes towards the increasing direction, when the volume changes and exceeds the deviation value set by the control system, the system controls the auxiliary pump driving mechanism 10 to reversely rotate, the auxiliary pump 9 is driven to reversely rotate, the auxiliary pump 9 pumps the oil in the high-pressure cavity to flow into the energy accumulator 8, until the oil cylinder extension amount of the oil cylinder 11 is recovered to the initial set value, and therefore the volume of the high-pressure cavity of the oil cylinder 11 is kept constant. When the oil in the energy accumulator 8 is consumed, the auxiliary pump 9 can suck oil from the oil tank 18 through the oil suction one-way valve 7.
When the system is stopped and oil cylinder leakage and temperature difference compensation are not needed, the pressure in the energy accumulator 8 can be relieved through the energy release valve 6. At this time, the energy release switch valve 61 is energized, both coils a and b of the main directional control valve 5 are de-energized, and the oil in the accumulator 8 flows back to the oil tank 18 through the energy release switch valve 61, the one-way throttle valve 62, the second shuttle valve 1312, the main directional control valve 5, and the oil filter 4.
In conclusion, the bidirectional gear pump is arranged, and the change of the extending length and the extending direction of the oil cylinder is detected through the displacement sensor, so that the compensation of the volume change of an oil cavity of the oil cylinder caused by internal leakage and temperature difference is realized, the extending length of the oil cylinder can be ensured to be stable, and the aim of safety and stability of an aerial work platform is fulfilled finally; by arranging the auxiliary power, a standby power supply or a vehicle-mounted battery can be adopted to provide energy, the normal functions of the main power and a main pump oil way are not influenced, and a leakage and temperature difference compensation oil way can be flexibly configured as required; by arranging the energy accumulator, the main power is filled with liquid when working, and the power consumption of the auxiliary power can be reduced when the main power stops working, so that the cruising ability of a standby power supply or a vehicle-mounted battery is prolonged, and the working time is ensured to be as long as possible. The oil cylinder holding valve has the functions of a common bidirectional balance valve, and the arranged shuttle valve can automatically select a high-pressure oil path, so that the automatic liquid filling of the energy accumulator and the automatic identification of the high-pressure oil chamber of the oil cylinder are realized, the logic of the oil path is clear, the structure is simple, and the work is efficient.
In the description of the present invention, it is to be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; may be mechanically coupled, may be electrically coupled or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (12)
1. A cylinder hydraulic system, characterized in that the cylinder hydraulic system comprises:
the oil cylinder working oil way of the oil cylinder (11) comprises a rodless cavity connecting oil way and a rod cavity connecting oil way;
the oil cylinder retaining valve (13) is arranged in the oil cylinder working oil path and used for keeping the oil cylinder (11) in an extending state, the oil cylinder retaining valve (13) comprises a first shuttle valve (1311), a first comparison oil port of the first shuttle valve (1311) is connected with the rodless cavity connecting oil path, and a second comparison oil port of the first shuttle valve is connected with the rod cavity connecting oil path;
and the leakage and temperature difference compensation oil circuit (L1) is provided with an oil liquid pumping mechanism and is connected with the third oil inlet and outlet of the first shuttle valve (1311).
2. The cylinder hydraulic system as claimed in claim 1, characterized in that the oil pumping mechanism comprises an auxiliary pump (9) capable of rotating forward and backward and an auxiliary pump driving mechanism (10) for driving the auxiliary pump (9), wherein a first pumping oil port of the auxiliary pump (9) is connected with a third oil inlet and outlet of the first shuttle valve (1311); the oil cylinder hydraulic system comprises an energy accumulator (8), and the energy accumulator (8) is connected with a second pumping oil port of the auxiliary pump (9) through an energy accumulator connecting oil way.
3. The cylinder hydraulic system according to claim 2, characterized in that the cylinder hydraulic system comprises:
and the auxiliary oil suction oil path is connected between the second pumping oil port of the auxiliary pump (9) and the oil tank (18) in parallel with the energy accumulator connecting oil path, and an oil suction one-way valve (7) which enables oil to flow to the auxiliary pump (9) from the oil tank (18) and is cut off reversely is arranged in the auxiliary oil suction oil path.
4. The cylinder hydraulic system according to claim 2, characterized in that the cylinder holding valve (13) includes a second shuttle valve (1312) disposed in parallel with the first shuttle valve (1311), a first comparison port of the second shuttle valve (1312) being connected to the rodless chamber connection oil path and a second comparison port being connected to the rod chamber connection oil path;
and, the cylinder hydraulic system includes:
and the accumulator oil supplementing and pressure releasing oil path (L2) is connected with a third oil inlet and outlet of the second shuttle valve (1312).
5. The cylinder hydraulic system according to claim 4, characterized in that an energy release valve (6) for controlling the oil of the accumulator (8) to flow out towards the second shuttle valve (1312) to release energy is arranged in the accumulator oil supplementing and pressure releasing oil path (L2), and the energy release valve (6) comprises an energy release switch valve (61) and a one-way throttle valve (62) which are arranged in series.
6. The cylinder hydraulic system according to claim 1, characterized in that the cylinder hydraulic system comprises:
the main reversing valve (5) comprises a main valve oil inlet (P), a main valve oil return port (T), a first working oil port (A1) connected with the rodless cavity connecting oil way and a second working oil port (A2) connected with the rod cavity connecting oil way;
the main reversing valve (5) comprises a middle stop position, and the first working oil port (A1) and the second working oil port (A2) are communicated with the main valve oil return port (T) at the middle stop position.
7. The cylinder hydraulic system according to claim 6, characterized in that the cylinder hydraulic system comprises:
the main pump (1) is connected with the main valve oil inlet of the main reversing valve (5) through a main pump oil feeding way;
and the unloading electromagnetic valve (3) is connected between the main pump oil supply channel and the oil tank (18).
8. The cylinder hydraulic system according to claim 1, characterized in that:
the auxiliary pump (9) is a bidirectional gear pump; and/or
The oil cylinder holding valve (13) comprises a balance valve group arranged in the oil cylinder working oil way.
9. The cylinder hydraulic system according to any one of claims 1 to 8, characterized by comprising:
the displacement sensor (12) is used for detecting the oil cylinder extension amount of the oil cylinder (11); and
a controller configured to:
acquiring an oil cylinder elongation signal of the displacement sensor (12) and determining the change direction and the change value of the oil cylinder elongation of the oil cylinder (11);
determining that the change value is greater than a set value;
and correspondingly controlling the forward rotation starting or the reverse rotation starting of the oil liquid pumping mechanism according to the change direction until the change value is zero.
10. The cylinder hydraulic system according to any one of claims 1 to 8, characterized by comprising:
the first pressure sensor (16) is used for detecting the oil pressure of a rod cavity of the oil cylinder (11) or a connecting oil way of the rod cavity;
the second pressure sensor (17) is used for detecting the oil pressure of a rodless cavity of the oil cylinder (11) or a rodless cavity connecting oil way; and
a controller configured to:
oil pressure detection values of the first pressure sensor (16) and the second pressure sensor (17) are obtained in real time, and a high-pressure cavity of the oil cylinder (11) is determined;
determining that the oil pressure detection value of a high-pressure cavity of the oil cylinder (11) is lower than a set pressure maintaining value;
and controlling to start the oil pumping mechanism and pumping oil to a high-pressure cavity of the oil cylinder (11) for pressure maintaining.
11. The cylinder hydraulic system according to claim 10, characterized in that a dwell check valve (15) is provided in the leakage and temperature difference compensation oil path (L1), the dwell check valve (15) being arranged such that oil can be pumped from an oil pumping mechanism to the first shuttle valve (1311) and be blocked in the opposite direction.
12. An aerial work machine, characterized in that the aerial work machine comprises a cylinder hydraulic system according to any one of claims 1-11.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210876410.7A CN115324960A (en) | 2022-07-25 | 2022-07-25 | Oil cylinder hydraulic system and overhead working machine |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210876410.7A CN115324960A (en) | 2022-07-25 | 2022-07-25 | Oil cylinder hydraulic system and overhead working machine |
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| CN115324960A true CN115324960A (en) | 2022-11-11 |
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| CN202210876410.7A Pending CN115324960A (en) | 2022-07-25 | 2022-07-25 | Oil cylinder hydraulic system and overhead working machine |
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